Methods for improving power consumption in communications networks are getting more and more important for telecommunication operators. Operators do not only care about the capacity of the network nodes, but also the capacity per watt of the network nodes. There are several current power consumption improvement methods which are currently used, and three of them will now be discussed:
One existing method is to improve power consumption of a network node's processor by automatically transitioning the processors hardware components into a lower power state when there is no traffic to the hardware components such that there is no load on the hardware components. This is a processor level power consumption technology. This means if there is no load on the processor's board, the processor will automatically go into low power state. A state may also be referred to as a mode. In a network node, such as for example a Serving General packet radio service Support Node-Mobility Management Entity (SGSN-MME) or an Evolved Packet Gateway (EPG) node, there is always some traffic between boards such as e.g. keep alive messages etc. Such traffic may involve statistics, few subscribers, management, ping-pong alive messages, inter boards' message etc. This type of processor level power consumption technology cannot save much power, since most of the devices are always still alive, i.e. there is always load on the hardware components due to traffic. Therefore, this method is not suitable to improve power consumption.
Another method to improve power consumption is to use a virtualization technology. A virtualization technology may be described as the creation of a virtual rather than actual version of a hardware platform, operating system, storage device, or network resources. Live migration is a process used in a virtualization technology and allows a server administrator to move a running Virtual Machine (VM) or application between different physical machines without disconnecting the client or application. For a successful live migration, the memory, storage and network connectivity of the virtual machine needs to be migrated to the destination. Live migration is supported by some virtualization hypervisors, i.e. a unit that creates and runs virtual machines, such as e.g. a Kernel-based Virtual Machine (KVM). Migrating the running virtual machines to one physical machine is performed when the load is not that high. In a network node, virtualization is seldom used due to performance and latency issues. Even though existing technologies may address these issues, moving existing network nodes to cloud computing is impractical in a near future due to security, network speed, availability, legacy interfaces, CAPital EXpenditure (CAPEX) etc. The cloud computing mentioned above may be described as use of computing resources, i.e. hardware and/or software, which are delivered as a service over a network, e.g. the Internet. The name cloud comes from the use of a cloud shaped symbol as an abstraction for the complex infrastructure it often has in system diagrams.
A further method for improving power consumption is to use a power on/off control strategy. The components of a network node are then dynamically turned on/off based on the load in the components. The components may be also referred to as a board, a blade or a physical machine. However it is very hard to anticipate whether the powered off servers are not needed for some predictable period of time. When the power of several servers is turned on again, the recovery is too long. Hardware initialization, operating system startup, process startup, configuration and taking back the contexts when a server turns on again will take more than three minutes.